Mark some disabled tests as flaky to increase test coverage.

net/disk_cache/backend_unittest.cc

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/basictypes.h"
 #include "base/file_util.h"
 #include "base/path_service.h"
 #include "base/platform_thread.h"
 #include "base/string_util.h"
 #include "net/base/io_buffer.h"
@@ skipping 1395 matching lines @@
 }
 
 TEST_F(DiskCacheBackendTest, DisableSuccess4) {
   ASSERT_TRUE(CopyTestCache(L"bad_rankings"));
   DisableFirstCleanup();
   SetDirectMode();
   InitCache();
   BackendDisable4();
 }
 
-// Flaky, http://crbug.com/21110. Don't re-enable without a real fix or adding
-// more debugging info!
-TEST_F(DiskCacheBackendTest, DISABLED_NewEvictionDisableSuccess4) {
+// Flaky, http://crbug.com/21110.
+// TODO(rvargas): Add more debugging code to help identify the root cause.
+TEST_F(DiskCacheBackendTest, FLAKY_NewEvictionDisableSuccess4) {
   ASSERT_TRUE(CopyTestCache(L"bad_rankings"));
   DisableFirstCleanup();
   SetDirectMode();
   SetNewEviction();
   InitCache();
   BackendDisable4();
 }
 
 TEST_F(DiskCacheTest, Backend_UsageStats) {
   MessageLoopHelper helper;
@@ skipping 142 matching lines @@
   EXPECT_EQ(kDefaultSize * 5 / 2,
             disk_cache::PreferedCacheSize(large_size * 100 / 2));
   EXPECT_EQ(kDefaultSize * 5 / 2,
             disk_cache::PreferedCacheSize(large_size * 500 / 2));
 
   EXPECT_EQ(kDefaultSize * 6 / 2,
             disk_cache::PreferedCacheSize(large_size * 600 / 2));
   EXPECT_EQ(kDefaultSize * 7 / 2,
             disk_cache::PreferedCacheSize(large_size * 700 / 2));
 }